Effect of methionine supplement on physical responses and neurological symptoms in broiler chicks fed grass pea (Lathyrus sativus)-based starter ration

Starter feeding experiments of broiler chicks with raw grass pea (Lathyrus sativus L.) supplemented with different levels of DL-methionine were undertaken for 4 weeks to assess the toxicity of grass pea-based feed and to correlate it with neurological symptoms. Four hundred fifty day-old broiler chicks were divided into two groups and were given formulations containing 35% (ration I) or 98.5% (ration II) grass pea, respectively. Each ration included controls and treatments with added methionine of four different concentrations. Feed intake, weight gain and feed conversion efficiency (FCE) were much higher in ration I than in ration II and these parameters significantly improved by addition of methionine in both rations. Significant increase of neurological signs with higher grass pea intake and significant reduction of acute neurological signs with addition of methionine were observed. Tolerance for grass pea was enhanced with increasing methionine in the diet and with age. Despite a similarity in the initial intake, a significant (p ⩽ 0.05) increase in the final feed intake by the chicks with methionine addition was found in both rations. These results suggest that methionine can improve a grass pea-based diet for broiler chicks and especially can protect young chicks from neurological symptoms.